Incandescent electric lamp.



G. C. WEBSTER. I

Patented Sept. 2, I902.

INGANDESCENT ELECTRIC LAMP.

(No Model.)

7 WITNESSES: I: 1

'JQMM (Application filed Dec 30, 1901.

/N VENTOR 4 TTOHNE rs 2o bulb provided with my invention.

UNITED STATES PATENT FFICE.

GLENN CANNON WEBSTER, OF l/VARREN, OI-IIO, ASSIGNOR TO THE STER- LING ELECTRICAL MANUFACTURING COMPANY, OF WARREN, OHIO, A

CORPORATION OF OHIO.

INCANDESCEN'T ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 708,432, dated September 2, 1902. Application filed December 30, 1901. Serial No. 87,724. (No model.)

dent of Warren, in the county of Trumbulland State of Ohio, have made certain new and useful Improvements in Incandescent Elec tric Lamps, of which the following'is aspecification.

It is the object of my invention to provide IO an incandescent lamp Whose filament shall be so constructed and arranged as toproduce a maximum and symmetrical distribution of light-rays,or, in other words, the same measurement of maximum candle-power at every point in a horizontal and vertical plane.

I The invention is hereinafter set forth and shown in the accompanying drawings, in which-- Figure 1 is a side view of an incandescent Fig. 2 is a side view of the filament and anchor. Fig. 3 is a horizontal section on theline 3 3 of Fig. 1.

The glass bulb A has the usual form. The pendent glass mount C is sealed within the top a, and conducting-wires a pass through and project from the same, as shown. To these wires a the ends of the carbon filament B are attached, as usual in this class of lamps. The filament B is wound spirally, there being 0 three convolutions 1 2 3. Thereare in fact two spirals, which are alike in form and arrangement. Thus the lower bend 1 of the double spiral merges into the two central convolutions 2, and these again into the upper 5 convolutions 3, whose terminals connect with the wire conductorsc. It will be seen that the spirals are wound in opposite directions and the convolutions 1 2 3 are symmetrically arranged one exactly opposite another hori- 4o zontally. An important characteristic is the relative diameters of the several convolutions 1 2 3, the same difiering, as shown, so'that when seen in end view, as in Fig. 3, the convolutions appear in different horizontal planes. The upper convolutions 3 are narrower than the lower ones 1, and the central ones 2 are wider than the latter, and hence are obtained. Filaments have been heretofore so constructed as to produce superior illumination in a vertical plane or downward direction and others have given a superior lateral distribution; but in. my invention I have attained both effects by the arrangement of spirals with reference to each other.

To steady and support the filament B, I employ the glass anchor D, which depends from the mount a and is formed integrally therewith. It is provided with a wire extension D, which is rigidly attached to the center of the lower bend or convolution 1 of the filament B. This anchor D serves another important function in that it draws to itself by static induction the carbon-dust or fine particles'of carbon which are given off from the filament as it grows old andwhich are ordinarily deposited on the bulb, and thereby obscure'the' transmission of light to a considerable extent.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

The improved electric incandescent lamp, comprising the glass bulb, a central, pendent, translucent anchor and the double spiral filament having a bottom loop attached to said anchor and a series of convolutions symmetrically arranged opposite each other and placed atdifierent distances from the anchor, as shown and described for the purpose specified.

GLENN CANNON WEBSTER.

Witnesses:

A. S. PHELPS, WM. OoALE. 

